Rectifier device for three-phase generators in vehicles

ABSTRACT

The rectifier device has a metallic front cooling plate and a rear cooling plate spaced from each other and extending parallel to each other; positive diodes arranged on one cooling plate and negative diodes arranged on the other cooling plate; a printed circuit board made of insulating material fastened between the cooling plates and having conductors for connecting the diodes with each other and also with a three-phrase generator; electrical connection device for making electrical connection with the front cooling plate comprising a threaded bolt having a flange, an annular shoulder and an axial pin projecting into an opening of the rear cooling plate, the threaded bolt being pressed in a hole in the front cooling plate and the flange and shoulder being dimensioned so that the annular shoulder contacts on a rear side of the front cooling plate, and a nut screwed on the threaded bolt from a front side of the front cooling plate to secure the threaded bolt in the hole; and an insulating material bush received in the opening for electrically insulating the threaded bolt from the rear cooling plate.

BACKGROUND OF THE INVENTION

The present invention relates to a rectifier device for three-phasegenerators in vehicles.

More particularly it relates to a rectifier device having two metalliccooling plates, and diodes inserted in the latter and having a printedcircuit board and a positive connection including a threaded bolt.

In a rectifier device of this type known from the German Utility Model G87 11 178 a connecting bolt for the connection of the rectifier device,which connection is designated by B+ according to German IndustrialStandard, is inserted into the outer cooling plate of the two coolingplates of the rectifier diodes lying parallel at a distance to oneanother in that it is pressed into a corresponding hole of the outercooling plate with a flange and contacts the annular shoulder of thescrew head at the back of the cooling plate. The threaded bolt istightly screwed to the cooling plate with a nut for protection. Therectifier device is mounted at the so-called B side of the three-phasegenerator. After the generator is installed in the vehicle a connectioncable for the positive pole of the vehicle battery is securely screwedon to the free end of the threaded bolt.

A disadvantage in such solutions consists in that forces can act on theconnection during strong vibrations and high starting torques andbending moments resulting in a deformation of the cooling plate orloosening of the fastening at the flange.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide arectifier device which avoids the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide arectifier device in which forces acting on a connecting bolt providingan electrical connection to the front cooling plate are distributed sothat the bolt can withstand required stresses.

According to the invention, the rectifier device for a three-phasegenerator of a vehicle, comprises a metallic front cooling plateprovided with a hole and a rear cooling plate provided with an opening,the cooling plates being spaced from each other and extending parallelto each other; a plurality of positive diodes arranged on one coolingplate and a plurality of negative diodes arranged on the other coolingplate; a printed circuit board made of insulating material fastenedbetween the front and rear cooling plates and having electricalconductors for connecting the diodes with each other and also with athree-phrase generator; electrical connection means for makingelectrical connection with the front cooling plate comprising a nut anda threaded bolt having a flange, an annular shoulder and an axial pinprojecting into the opening of the rear cooling plate, the threaded boltbeing pressed in the hole in the front cooling plate and the flange andshoulder being positioned and dimensioned so that the annular shouldercontacts on the rear side of the front cooling plate, the nut beingscrewed on the threaded bolt from the front side of the front coolingplate to secure the threaded bolt in the hole; and insulating means forelectrically insulating the threaded bolt from the rear cooling plate,the insulating means being received in the opening and receiving theaxial pin.

When the rectifier device is designed in accordance with the presentinvention, it has the advantage that the forces of vibrations, startingtorques and bending moments are transmitted into the two cooling plates.The bending forces in particular are ineffective since they aretransmitted into the two cooling plates parallel to the plate planes.Accordingly, a deformation of the positive cooling plate is no longerpossible. Another advantage consists in that this solution can berealized without additional structural component parts.

A particularly advantageous construction consists in that the insulatingmaterial bush for the rear pin of the threaded bolt of the positiveconnection of the rectifier device is formed on at the printed circuitboard located between the two cooling plates.

A metal bush is supported in a particularly suitable manner in aprotective cap of insulating material in a floating manner and so as tobe fixed with respect to rotation relative to it to prevent or reducestarting torques at the fastening point of the threaded bolt at thepositive cooling plate. The threaded bolt projects out through the metalbush. The metal bush is advisably provided with a hexagonal outercontour and is guided into a hexagon receptacle of the protective cap soas to be fixed with respect to rotation relative to it. Further, themetal bush is advantageously secured against falling out of the hexagonreceptacle of the protective cap in that a plurality of radialprojections are formed on at the end areas of the hexagon receptacle ineach instance.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the rectifier device of a three-phasegenerator according to the invention and FIG. 2 shows a cross sectionthrough this device according to line II--II from FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT

The construction of the rectifier device, according to the invention,whichis designated by 10, is composed in a known manner (see G 87 11178) of a sandwich-type arrangement of two metallic cooling plates 11,12 extending parallel at a distance to one another. A plurality ofpositive diodes 13 are inserted in the outer positive cooling plate 11which can be seen in FIG. 1. Negative diodes 14, only one of which canbe seen in FIG. 2, are inserted in the rear negative cooling plate 12.Further, a printed circuitboard 15 of insulating material is fastenedbetween the two cooling plates 11, 12. Conductors, not shown, forconnecting the diodes 13, 14 with one another and with connection wires,not shown, of the stator winding of therespective three-phase generatorare embedded in the printed circuit board 15. Moreover, the frontpositive cooling plate 11 is provided with a positive connection 16comprising a threaded bolt 17 at which a battery connection cable, notshown, of a vehicle is connected in the mounted state of the three-phasegenerator. The two cooling plates 11 and 12 and the printed circuitboard 15 located between the latter are securely connected with oneanother by three hollow rivets 18 so as to be electrically insulated.The rectifier device 10 is securely screwed to an end shield of thethree-phase generator by three screws which are guided through thesehollow rivets 18. After the rectifier device 10 is mounted at thethree-phase generator, the diodes 13 and 14 are electrically connectedwith the connection wires of the stator winding by a plurality ofexternal crimp connectors 19 in the printed circuit board 15.

The positive connection 16 which can be seen in cross section from FIG.2 is connected with the positive cooling plate 11 so as to beelectrically conducting in that its threaded bolt 17 is pressed into acorresponding hole of the cooling plate 11 with a flange 20. Thethreaded bolt 17 contacts the rear of the cooling plate 11 with anannular shoulder 21 located behind the flange 20. It is securely screwedto the cooling plate 11 in addition by a nut 22. The threaded bolt 17projects into an opening 24, preferably into a hole of the rear coolingplate 12, with an axial pin23 formed on behind the annular shoulder 21.Since this cooling plate 12 isconnected to negative potential, the pin23 is received in an insulating material bush 25 which is inserted intothe opening 24. The insulating material bush 25 is formed on at theouter area of the printed circuit board 15 which is clamped in betweenthe positive cooling plate 11 and thenegative cooling plate 12.

The rectifier device 10 is covered externally by a pot-shaped protectivecap 26 which has venting slits in its base as well as openings for theconnections of the rectifier device. To keep torque loads as far awayfromthe flange 20 as possible at the positive connection 16 whenscrewing on orunscrewing a cable, the front end of the threaded bolt 17projects through a metal bush 27. The bush is supported in an opening ofthe protective cap26 in a floating manner and so as to be fixed withrespect to rotation relative to it. For this purpose a collar 28 isformed on at the opening of the protective cap 26. The collar 28 has ahexagon receptacle 29 at theinside in which the metal bush 27 is axiallyguided and secured with respect to rotation by a hexagonal outercontour. To prevent the metal bush 27 from falling out of the hexagonreceptacle 29 of the protective cap 26, three radially directedprojections 30 which are uniformly distributed along the circumferenceare formed on at the protective cap 26at the front end of the hexagonreceptacle 29 and an additional three radially inwardly directedprojections 31 are provided in the rear area ofthe hexagon receptacle29. Of the projections 30 and 31, only one projection 30 and 31 can beseen in FIG. 2.

Since the rectifier device 10 is usually situated vertically afterinstalling the generator in the vehicle, the forces occurring at thepositive connection 16 during vibrations are transmitted via the flange20into the positive cooling plate 11 on the one hand and via the pin 23and the insulating material bush 25 into the negative cooling plate 12on the other hand. Bending forces occurring at the threaded bolt via thepin 23 when connecting or removing a connection cable are likewiseabsorbed substantially by the rear cooling plate 12 parallel to theplane of the cooling plate and a bending of the front cooling plate 11is accordingly reliably prevented. Moreover, the floating metal bush 27in the protectivecap 26 prevents the torque from being transmitted tothe lower nut 22 when loosening the connection cable even when theconnection is rusted on, since the metal bush 27 transmits these forcesto the hexagon receptacle 29 of the protective cap 26 via its outercontour. A loosening of the threaded bolt 17 is accordingly reliablyprevented.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in arectifier device for three-phase generators in vehicles, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.
 1. A rectifier device for athree-phase generator of a vehicle, said rectifier device comprising ametallic front cooling plate having a front side and a rear side andprovided with a hole, and a rear cooling plate provided with an opening,said cooling plates being spaced from each other and extending parallelto each other; a plurality of positive diodes arranged on one of saidcooling plates and a plurality of negative diodes arranged on another ofsaid cooling plates; a printed circuit board made of insulating materialfastened between said front and rear cooling plates, said printedcircuit board having electrical conductors for connecting said diodeswith each other and also with said three-phase generator; electricalconnection means for making electrical connection with said frontcooling plate comprising a nut and a threaded bolt having a flange, anannular shoulder and an axial pin projecting into said opening of saidrear cooling plate, said threaded bolt being pressed in said hole insaid front cooling plate, and said flange and said shoulder beingpositioned and dimensioned so that said annular shoulder contacts onsaid rear side of said front cooling plate, the nut being screwed onsaid threaded bolt from said front side of said front cooling plate tosecure said threaded bolt in said hole; and insulating means forelectrically insulating said threaded bolt from said rear cooling plate,said insulating means being received in said opening and receiving saidaxial pin.
 2. A rectified device as defined in claim 1, wherein saidinsulating means comprises an insulating material bush received in saidopening, said axial pin of said threaded bolt being received in saidinsulating material bush.
 3. A rectifier device as defined in claim 2,wherein said insulating material bush is formed on said printed circuitboard in the region between said cooling plates.
 4. A rectifier deviceas defined in claim 1, and further comprising a protective cap ofinsulating material and having an opening, said threaded bolt projectingthrough said opening of said protective cap in a floating manner and soas to be fixed with respect to rotation relative to said protective cap.5. A rectifier device as defined in claim 4, wherein said protective caphas a collar bordering said opening.
 6. A rectifier device as defined inclaim 5; and further comprising a metal bush which is supported in saidopening of said protective cap and receives said threaded bolt.
 7. Arectifier device as defined in claim 6, wherein said collar of saidprotective cap has a hexagon receptacle, said metal bush having ahexagonal outer contour which is axially guided in said hexagonreceptacle of said collar.
 8. A rectifier device as defined in claim 7;and further comprising means for preventing falling out of said metalbush from said hexagon receptacle of said protective cap.
 9. A rectifierdevice as defined in claim 8, wherein said preventing means includes aplurality of projections which are directed radially inward and formedon end areas of said hexagon receptacle of said collar.